After ACL tears, younger patients and women more likely to need multiple surgeries

It’s a familiar scenario: after an initial surgery to repair a torn anterior cruciate ligament (ACL)—one of the four major ligaments that connect the shin bone to the thigh bone and hold the knee in place—there is a long period of physical therapy and follow-up with the doctor. Yet, and in some cases, patients find themselves going under the knife again—needing multiple surgeries to correct the problem, or at least minimize the discomfort. As it turns out, the need for additional repair after an initial ACL injury isn’t evenly distributed across the population. A study published in this month’s Journal of Bone and Joint Surgery finds that, after an ACL tear, women and people younger than 20 are more likely than others to need more than one knee surgery.

Part of the issue, of course, is that more ACL surgeries are being performed overall in recent years. Extrapolating from national data, researchers estimate that more than 100,000 such surgeries take place annually in the U.S. Yet this study, which examined the records of 70,547 patients who had reconstructive ACL surgery between 1997 and 2006 found that, while, across the board patients older than 40 were more likely to be readmitted into the hospital within three months after surgery due to complications or continued pain, those younger than 40 were actually more likely to need follow-up surgeries after the original ACL reconstruction.

For patients ages 20 and younger, the risk of needing an additional surgery was 82% higher than that of the general ACL injury population. That risk diminished substantially with age: 20-29 year-olds had a 43% higher risk; 30-39 year-olds had a 19% higher chance of needing additional procedures. Women were also 18% more likely than men to need multiple procedures, the study found.

Another trend that the researchers discovered—and which has been documented in medical disciplines other than orthopedics as well—was that patients whose surgeons were less experienced were more likely to need follow-up surgeries than patients whose doctors had more ACL reconstructions under their belts. (Hospitals and surgeons were considered less experienced if they had a lower volume of ACL surgeries each year—fewer than 24 for institutions and fewer than six for individual surgeons.)